I have Myford Super 7. Behind the chuck on the left hand side is a tapped hole(about M10), I think it is for a chuck guard. Does anyone know what thread it is?
I want to utilise this to hold a bolt that in turn will hold a proximity switch.
If you mean the one behind the chuck, it's 3/8" BSF. Incidentally, I doubt you will find any ISO metric threads on your S7, unless some owner has put it there.